A recent study from the World Health Organization
revealed that iron (Fe) deficiency anemia not only accounts for the most
prevalent nutrition disorder by affecting 2 billion people, but also for the
only one significantly present in industrialized countries. Approximately every
other pregnant woman as well as 40% of children under the age of six are
affected, when living in developing countries
(www.who.int/nutrition/topics/ida/en). Often people that live in rural places
have reduced access to a well-balanced diet, dietary supplements or fortified
staples. Especially in regions with prevailing malnutrition due to the lack of
accessibility of high quality nutritious food, numbers of affected people peak (Saltzman et al., 2013; Naranjo?Arcos and Bauer, 2016).
In humans, approximately 70% of the Fe is needed for
the production of hemoglobin and hence is involved in erythrocyte-mediated
oxygen transport in the blood whereas roughly 4% is needed for the myoglobin-mediated
transport within the muscle cells. The remaining Fe is utilized for energy
production (Scrimshaw, 1984). Hence, Fe deficiency anemia can
have a severe impact on the physical well-being and overall health. For
instance, Fe deficiency diminishes infection resistance by impairing the immune
system, alters cognitive performance, impairs growth and physical performance (Scrimshaw, 1984).
One long-term and cost-efficient way to counteract
this problem is to increase the amount of Fe in food staples. This can be done
by selective breeding or genetical modification of plants, in order to enrich their
edible parts with the needed Fe. This strategy however can only succeed if
certain basic principles are preserved, such as the combination of nutrient
enrichment with high yield (ensuring profitability), a decrease in Fe
deficiency anemia in humans (ensuring efficiency) as well as acceptance by
farmers (ensuring applicability) (Bouis et al., 2011; Saltzman et al., 2013). This
biofortification approach has been applied e.g.
in rice plants by overexpressing Fe storage, homeostasis, uptake, translocation
or transportation genes (Masuda et al., 2013). Recently, a new variety of beans,
which are rich in Fe, has successfully been reported to increase Fe levels in
Rwandan women, highlighting the potential of biofortification (Haas et al., 2016).
For a successful application of this promising tool to
enhance bio-available nutrients in staple food, it is needed to understand the
importance of nutrients for plants in general and to decipher plant nutrient uptake
and homeostasis systems in-depth.